Wireless communications traffic is increasing. Accompanying this increase, for example, utilization of available channels (white space) such as television broadcast frequency bandwidths is being investigated (for example, refer to J. Wang, S. Filin, H. Harada, “IEEE802.19-11/0067r0”, NICT, July 2011).
Nonetheless, with conventional techniques, when multiple radio apparatuses use the same frequency in the same area, if the communications schemes of the radio apparatuses differ, a problem arises in that interference control is complicated and interference becomes great.